For those of you who believe in and use line conditioners, which do you recommend? I know some people say that aren't needed, but if you are going to use one, which is the way to go? Panamax, Acoustics, Monster? What rating? What price range? Console or strip?

Thanks,
Jeff

P.S. the circuit city guy recommend the Monster HTS 1600. I know Monster products are good but terribly overpriced! What could offer that same quality and protection, but be a reasonable price?

Why do you feel that monster products are good? I have yet to read one review that makes me belive that they are more than average. Do you have a problem with your electricity in your home?

As for the circuit city, why are you taking the word of a $7/retail monkey for your AV needs? What knowledge does he have that you can't by looking it up online?

As for botiques, they push the conditioners because of the HUGE margins they make on it. I know the guys at a local store get a $200 spiff on Monster power "conditioners"

Why do you feel that monster products are good? I have yet to read one review that makes me belive that they are more than average. Do you have a problem with your electricity in your home?

As for the circuit city, why are you taking the word of a $7/retail monkey for your AV needs? What knowledge does he have that you can't by looking it up online?

As for botiques, they push the conditioners because of the HUGE margins they make on it. I know the guys at a local store get a $200 spiff on Monster power "conditioners"


What surge protector would you buy to be sure equipment is protected?

And I am guessing you do not believe in line conditioners (some stuff I've read online convinces me it is worth thinking about -- but I am an AV noob so I need to read more...)

If your primary goal is to protect your equipment then the recommended thing to do is to first go with what's commonly referred to as a whole house approach where the device is located either at the breaker box or at the meter. Now, this assumes you own your own property. This will provide good protection for everything in your home from the vast majority of incoming surges be they a result of lightning, a pole transformer dropping, and other sundry grid problems that crop up from time to time. This doesn't need to be expensive and you'll likely find that Home Depot, Lowes, or a local electrical supply shop has devices that'll do the job.

After that, it's still a good idea to have plug-in devices since you want to further throttle down anything that came through. The thing is, just about anything will work if you first proactively address what I mentioned above. My suggestion would be to set some budget here and select units from companies like TrippLite, Panamax, Belkin, APC, Monster, or whomever that hit your price point. Then try and figure out what they do for you in terms of functionality. By that I mean that you ought to consider and prioritize what's important to you. The number of switched/unswitched outlets, 12 volt triggers, sequenced turnons, spacing for walwarts, maybe an outlet in the front...things like that. Any unit you buy is going to have filtration for your AC, probably AC isolation between adjacent pairs of outlets, outlets dedicated for amps (a different kind of filtration designed to alleviate the concerns, real or imagined of people who think that too much or the wrong kind of filtration can reduce an amp's dynamics), and other devices.

At this point, if you've got it narrowed down to two or three, then you can further segment them according to things like joule rating, published attenuations, warranty, appearance (why not?!), and other features like the ability to dim the display, display the voltage, whatever.

Don't get hung up on which one is more musical or makes your system sound better. Somewhere on the web is a review that speaks highly of just about anything so it's good that you be practical about this.

I know some people say that aren't needed, but if you are going to use one, which is the way to go?
That's like saying, if you are going to waste your money on a product that does nothing, which product would you buy! It is highly unlikely that you live in an area where you would need a power conditioner. Do you have a lot of black outs in your neighborhood? If not, you'd probably be better served putting that money into speakers or room treatments.

I had a problem at one time with an early generation B&K preamp/decoder that regularly lost its memory when my swimming pool pump or A/C unit would switch on. I bought a Furman AR-1215 which is actually a voltage regulating unit. It has an autotransformer and can hold the output voltage constant at 120 volts with line voltage variations between 97 and 141 volts. It solved the problem but in the end I wound up getting rid of the unit for a better piece of gear. I think the B&K unit had some design problems and really had pretty poor noise immunity. Furman makes good gear if you really think you need it. A lot of the Roadies use Furman gear but they have a lot of gear at risk in a lot of variable power situations.

..Doyle

A lot of the Roadies use Furman gear but they have a lot of gear at risk in a lot of variable power situations.

..Doyle

We use them because we get them for free in exchange for advertising, and they work, and they have lots of outlets, pretty lights, a outlet on the front for the vidiot to plug something into etc..
:p

Power filtering has an impact on certain systems; it's clearly audible in ABX tests under many conditions.

Currently, I have my money in the Transcendent Sound Balanced Power Supply (http://www.transcendentsound.com/power_supply.htm) but I may go with something else in the end. The rest of the equipment isn't here to listen to yet. Note, though, that I'm only using this for a pre-amp, as I'm putting in active speakers.

Power filtering has an impact on certain systems; it's clearly audible in ABX tests under many conditions.

Currently, I have my money in the Transcendent Sound Balanced Power Supply (http://www.transcendentsound.com/power_supply.htm) but I may go with something else in the end. The rest of the equipment isn't here to listen to yet. Note, though, that I'm only using this for a pre-amp, as I'm putting in active speakers.

So are you saying here that a line conditioner *is* worthwhile?
See, this is where it gets confusing...

....yup! And it will stay confusing until you either purchase or leave the conditioner out of the mix. At that point you will become of one camp and opposed to the other camp. That is the way it goes.

I considered for some time whether to buy a power conditioner. I did a lot of research on the topic. But in the end, it came down to the fact that I did not find a single respected electrical or audio engineer recommend the purchase of one or measure any audio improvement when one was in use. In fact, every engineer I came across recommended against wasting your money on one (unless you live in a country with variable power distribution, which does not include North America or Western Europe). So you will have to do your own research and make up your mind. If you can afford it, and it gives you peace of mind, go for it as it can't hurt. Just realize that it may not help.

One thing you have to take into account when using a line conditioner is the grounding. Most typically all of the receptacle grounds in the conditioner are connected together. If you do not have all of your equipment plugged into that same conditioner, you do have the potential for some ground loop issues. Not that they cannot be solved but just be aware that in trying to solve one problem, you may create another.

..Doyle

If your primary goal is to protect your equipment then the recommended thing to do is to first go with what's commonly referred to as a whole house approach

Or just make sure you have adequate coverage on your home-owner's insurance. That's cheaper, and most people already have that anyway.

It amazes me how effective the scare tactics these companies use are to an uneducated public. For all of my 58 years I've lived in a normal house with normal AC power, and I have never once lost any device to a power surge.

--Ethan

Or just make sure you have adequate coverage on your home-owner's insurance. That's cheaper, and most people already have that anyway.

It amazes me how effective the scare tactics these companies use are to an uneducated public. For all of my 58 years I've lived in a normal house with normal AC power, and I have never once lost any device to a power surge.

--Ethan



I have had my own house since I was 20, 20 years now and lost one TV. Insurancec would have covered itbut at the time Wal Mart replaced it free. Other than that I have never had issues with it. And I have vener had all these horrible ground buzz issues everyone else seems to have and I use the cheapest cables I can get even the ones right out of the DVD player box.

FWIW
I've lived in my home for 27 years with "knob and tube" (except A/V gear and kitchen) and never had a device get fried nor have any electrical (visual/audio) plagues. I use a $20 power strip/surge protector for my A/V gear. Hasn't tripped once... yet. ;)

It's always a crap shoot with this sort of thing, Ethan. With insurance policies, you've got to read the policy very carefully to see if indeed you have protection for equipment against surges. Also, you need to find out what the nature of the insurance is. How are claims handled? Deductible? Prorated? What if the company challenges your claim? What steps do you need to take to substantiate your loss? I mean, we're not all in good hands are we? You may need to add a rider or modify your existing policy to get the kind of 'protection' you want, and that does come at a cost. Each and every year. Cheaper? Some policies offer discounts for installing a whole house. Some don't.

The whole house approach, which in my case was in the vicinity of $200, doing the work myself, wasn't onerous. I could've spent less. Prior to doing so, I'd lost a receiver which wasn't a big deal really. Wish I'd taken pics of the capacitors that looked like IED's! I've lost a well pump. That was a big deal.

Scare tactics? If you're talking about Monster, Brickwall, and others, sure. They're looking to sell you not only ineffective protection, but on a dollar spent per protected device basis, it's very expensive. That's why I recommend that if your goal is to deal with surges, you first go whole house and then add sundry devices where appropriate. It's also why I say don't look at a plug-in device as some sort of 'it's gonna make me safe and clean my power just peachy kind of thing'. Look at them as devices that enhance the usability of your system by providing a single point for plugging things into and adding additional functionality.

My personal recommendation is to practically evaluate our own level of paranoia. We ought to consider things like down time, inconvenience, and a host of other things that we all value differently, then act accordingly.

Well, I'll provide a contrary viewpoint. I switched over from DirecTV to Dish and my Dish DVR has had constant crashes and problems. I'm now on my 3rd unit. The power supplies in these things are HORRIBLE and require clean power. With an automatic voltage regulating UPS I have had _zero_ crashes (vs 2-3 per week) with the newest unit (crashed before, now stable). All other electronic equipment in my house is stable. Bottom line: some poorly designed equipment can benefit from (relatively cheap) power conditioning. You'll want something with active devices (no cables with passive circuitry, etc.). APC and others offer solutions ~$100 that work wonders. If you want whole-system protection then systems for telecom are available (for less than the audiophile options).

Then IMO... that's a poor design of the power supplies in the Dish DVR. If you've never had any issues in your home and only experienced issues with the Dish DVR, why should you go to any unnecessary expense? Let them address and resolve the problem.

Unless... it's intentional and the same people that manufacture the power supplies in the Dish DVR's also manufacture power conditioners. ;)

LOL! Greg, have you monitored the voltage in your home or tried different outlets that might be on a different circuit?

Which DVR do you have Greg? I have a couple 508s and a 622. I have not had any problems with the 622 since I got it in Feb of 2006. One of my 508s has lots of problems but that only started after they did a firmware update and it is pretty well documented on the dbstalk website. The most recent firmware upgrade fixed about half of the problems. Prior to the firmware upgrade about 8 months ago, the 508s were solid with no problems.

..Doyle

Scare tactics? If you're talking about Monster, Brickwall, and others, sure. They're looking to sell you not only ineffective protection, but on a dollar spent per protected device basis, it's very expensive.
Yes, that's my point, and that's where the vast majority of marketing dollars to promote this "power problem" snake oil goes.

The whole house approach, which in my case was in the vicinity of $200
Not to argue with you m'man, but let's keep this apples to apples. What would it cost for someone who is not handy or is too busy to DIY? More than the approx. $30 extra for a "replacement value" rider on their home insurance to cover a normal amount of stereo / HT gear?

This brings up a related issue - the cost and value of audio gear. A lot of people pay way more than needed for their gear. I'm not opposed to nice stuff! I have some nice stuff myself. But if someone has so much gear they can't afford proper insurance, something is very wrong.

--Ethan

unless you live in a country with variable power distribution, which does not include North America or Western Europe

I live in California. Specifically, I live in a bay area tract house with airline power distribution. I have graphs that show you wrong. In fact, I had an expensive Italian light fixture in my dining room where the transformer died TWICE before I gave up on it. Regular incandescent bulbs also blow with some frequency on certain of my circuits.

Above-ground distribution is bad not only because the lines are more prone to trouble in general (falling down, trees, etc), but also because they may act as radio antennas, funneling EMI into your entire household.

Finally, well designed equipment (typically, mil spec or commercial) will have well designed power supplies, that will manage to filter all that gunk out, and may even stand up to the highly variable power PG&E manages to pipe through those overhead lines to my place. However, more affordable consumer gear, with pinch-every-penny power supplies, might not be as lucky. If you combine these problems, you may end up with audible problems, which could be cured by sufficient power filtering.

PS: I'm an engineer, and a member of the AES. So there! :-)

Yes, that's my point, and that's where the vast majority of marketing dollars to promote this "power problem" snake oil goes.
And I agree 100% with your point there. That's why I say, don't look at the products as providing serious protection. It's only supplemental. Look at them for the other reasons I enumerated and value that accordingly. Filters and MOV's are cheap.

It'd also cost you the price of an electrician. I could've done it for less Ethan like I said. And for the $30 or so, I don't have to worry about down time. I also don't have to worry about anything else in my home that has microprocessors and electronic gizmos needing to be replaced. I don't have to worry about substantiating a claim. I might value that differently than you, but to me it has some intrinsic value. Also, you'll find that some insurance companies offer a discount for things like that. Like having a car alarm.

As bad as you think you've got it jwatte, you ought to see the mess in Florida with Florida Power and Lighting. Besides, Italian fixtures never work. They were designed by FIAT. You know, Fix It Again Tony. :D

... the mess in Florida with Florida Power and Lighting.

Or... Florida Power and Lightning. :D

Then IMO... that's a poor design of the power supplies in the Dish DVR. If you've never had any issues in your home and only experienced issues with the Dish DVR, why should you go to any unnecessary expense? Let them address and resolve the problem.I totally agree with you. If they were a stand-up company then there wouldn't be these problems. The 1st thing they suggest when you have a problem is to install a AVR UPS. I have the 622 unit and this is my 3rd unit... all 3 units have experienced the same problems on multiple outlets throughout the house. The UPS with voltage regulation has fixed the issue. Power to the home has been tested and is within industry norms.

BTW, my DirecTV DVR was rock solid the entire time I owned it. Now that DirecTV's prices have gone down I may switch back...

Can anyone give some info on these devices that take care of teh whole house, by the meter/ breaker box?

i live in the sf bay area as well, and consider our power system equivalent to that of a third world country (which some would say the bay area is generally!)...we can be sitting there in the middle of the afternoon on a normal day and the power will just die...happens frequently. that makes me wonder about power 'cleanliness' and makes me want to get a conditioner.

my question is whether there's a discernible difference in performance between, say belkin pure av, panamax and monster. the latter is more expensive, belkin the cheapest, but will i be fine with any of the above? i'm thinking of spending around $150 which gets me one of the better belkin units (pf31d), one of the lower end panamax (4300) or monster (used 3500)...

thx....

The power quality here in Florida is just fine. I have progress energy(florida power corp), Lightning is a different story. I think you guys should make a distinction between "dirty power" and outages. When the lights go out, thats one thing, but harmonics, EMI, sags and swells are another.

Power conditioners are for most people going to be a waste of money. Unless you have or live next to large nonlinear loads, an industrial park, a distribution station prone to alot of switching. Most power problems are going to be from the utility transformer to your outlet and the bulk of those are going to be bad connections. Grounding is one of the least understood and most neglected parts of the electrcal system.

I tend to agree with Chu Gai on this, get yourself surge protection. I think for the money it is alot less of a headache to replace the surge arrestor than making insureance claims, digging out your records, talking on the phone to the insurance company.........

I am also an engineer and members of societies.
IEEE- Institute of Electrical and Electronics Engineers

PES- IEEE Power Engineering Society

IEA- IEEE Industry Applications Society

NETA- InterNational Electrical Testing Association

I posted a few things JohnnyRey. Do a search under my name in the Audio Theory and tweaks forum. Use the posts option. If that doesn't turn up much that'll help you, I'll dig something up next week.

Can anyone give some info on these devices that take care of teh whole house, by the meter/ breaker box?

http://www.avsforum.com/avs-vb/showthread.php?t=701803

I have a Sq D panel, installed their "breaker style" surge protector. Takes the same space as a double pole breaker, easy to install as long as you are comfortable working inside your panel box. ;)

I came in here looking for some decent advice on line-conditioners and find nothing but nay-sayers. If you don't believe in using a certain product then go waste your time posting inflammatory comments elsewhere.

I, for one, just lost a computer monitor to small power surges. In my old house (which was a new house, by the way), my computer's speaker system would make a loud pop when I turned on the lights. Recently, my computer monitor crashed. I sense a connection. I did have a power strip, but it's "surge" light was on and I was told that means it's pretty much caput.

My currently problem is my sub amp sucks up so much power, it causes the TV to flicker under really heavy loads. I'd like to get a nice power conditioner maybe with a capacitor to help solve this since switching to another breaker isn't really an option.

So... anybody with useful input on this matter would be much appreciated.

If you found nothing but naysayers, then you didn't read carefully enough. The thread contained information as well as cautionary comments. The thing is, the term 'power conditioning' is bandied about very loosely by just about everyone. You need to define your problem or objective with respect to your incoming electricity and then search out products that meet those in a sensible manner.

With respect to your situation javanpohl you should determine just what's on your circuit as you may be approaching the limits of what your circuit can effectively handle. Also, you ought to try just temporarily using an extension cord and moving the sub further away from the TV (I'm just guessing that it's not too far away right now) to determine if the vibrations are causing the flickering. If the extension cord is long enough, then you can plug it into an outlet that's on a different breaker and observe what happens. Certainly, if your home is older, then you may need upgraded electrical service.

Javanpohl,

I agree with the above post. Chu and I are not bashing line conditioners. We only caution that they are not fix-all's. Treat the problem with the correct solution and not what BB, CC and Monster want to sell you. You will only end up with the same problems and less money in you pocket.

If you want to buy a line conditioner. By all means get one, you will feel better, but I look at power problems ALL the time and I would like to share what I have seen in the industry with you. I thought that was why we come here to AVS, to exchange ideas and experiences. I am no audio expert, heck I don't even mess in my user menu on my TV, but power quality I do know a thing or two.

Good luck with fixing your problems. if the line conditioner does the trick, great. If it doesn't we'll still be here to help you out.

If you live in Florida, you sure as hell deal with power problems!

Yeah I see a few lightning strike every once in a while :)

One thing that has me researching line conditioners is something that isn't often mentioned in these "is it snake oil or does it have benefits?" debates on line conditioners. I think this eternal conumdrum goes beyond "tweaking" because of the basic need to plug a lot of "stuff" in. I'm building my HT system, and I can forsee having upwards of 10 things to plug in, including two amplifiers and a sub.

I doubt I'd bother plugging amps and sub into anything other than dedicated circuits, but as soon as I move away from having 10+ outlets built into the wall, it begins to beg the question what do I plug everything into? And then, if I take the leap to plugging the pre/pro, the sat box, the dvd player, the kid's game machine, whatever else, into something other than just the wall outlets, it becomes a matter of finding something that does no harm... Surveying the pre-owned market (which would be the only way I'd ever spend money on something like this), it seems one could buy a basic Furman Elite conditioner for under $200 (closer to $100). However, I keep consistently hearing that balanced power conditioners are effective, and I'm seeing used Equitechs (and the balanced power-type better Furmans) going for as low as ~$800.

This leads to the summation of my question. Do I have an electrican put 10+ outlets into my wall, or should I take my non-amp type gear and plug it into an inexpensive Furman conditioner, or do I spend a little more (~$800) for balanced power?

This leads to the summation of my question. Do I have an electrican put 10+ outlets into my wall, or should I take my non-amp type gear and plug it into an inexpensive Furman conditioner, or do I spend a little more (~$800) for balanced power?

First add uo the amp draw on all your gear. Just because it has 10 or 8 outlets does not mean it can handle all of your gear.

Now in the multimillion dollar show I currently work at on the strip in Vegas we use Furman bars for all the gear. And on any tour I have ever been on we used them. They work, they provide handy things like lights and switched outlets and we do not need snake oil products to make our audio sound correct.

This leads to the summation of my question. Do I have an electrican put 10+ outlets into my wall, or should I take my non-amp type gear and plug it into an inexpensive Furman conditioner, or do I spend a little more (~$800) for balanced power?

Any further thoughts out there?

Well balanced power won't necessarily do anything for you unless you've got a problem that it's tailored for. Like speco said, see what your draw is for the equipment you have. You could always run two separate circuits and you don't need 10 or more outlets. My guess is something like one of the shelf mounted Belkins would provide most of the connections you need as well as some nice functionality to make your life easier.

...You could always run two separate circuits and you don't need 10 or more outlets. My guess is something like one of the shelf mounted Belkins would provide most of the connections you need as well as some nice functionality to make your life easier.

In terms of the "Do no harm" concern, outside of amps and sub, is there anything else in a typical HT system that should be plugged straight into the wall (pre/pro, display, etc.)? I kind of like the rack lights that are offered on some of the Furmans -- is there any functionality issues behind your Belkins suggestion?

If one of your concerns has to do with protecting against surges as from lighting strikes, the first thing I'd do is install a whole house surge protector or lightning arrestor. Those are invariably located within the breaker box and since you're considering running extra circuits, it can all be done while the electrician is there. Kill two birds and all that.

Then, and only then, consider your Furman, Belkin, TrippLite, Panamax, or whatever. A desireable goal would be to earth the bulk of the surge before it enters your home and then let your plug-in units handle the little that comes through, attenuating it to benign levels. Does this make sense?

Sounds like a good plan, as I certainly would be upgrading to 20 amp dedicated lines. I'm fortunate in that the equipment rack will (eventually) be built into a wall, with the rear of the gear open/exposed in an unfinished laundry/utility room that also has the breaker box in it. My main motivation is connectivity (aka no wall of 10+ oulets) without compromising the performance of anything, and then beyond that, making a selection that could bring any possible benefits to the table (hence my research into balanced power, et al.). There's a used Furman over on A'gon that's a 20 amp device -- in the approach that you've outlined, is there any benefit to 20 amps over 15 for whatever gear might be connected to it?

Balanced power helps in certain specific cases, especially when your gear actually has a grounded plug (and it's actually most common to help in tube-based designs, for esotheric electrical reasons, I'm told). There is a big difference between three things here:
1) Surge suppression and overvoltage protection: make sure your gear doesn't die
2) EMI noise filtering: reduce noise induced by the powerline
3) Balanced power: reduce noise caused by poor grounding design or leakage in circuits

Personally, I run the following set-up:
1) A dedicated circuit, with ~10 outlets:
TV
Powered Sub
6x Powered Speakers
A/V cabinet
This circiut is actually run through a relay, so that all outlets except for the A/V cabinet are broken when I turn off the AVR.
2) An AVR UPS with filtering (I use a Cyberpower, other people swear by APC or other brands). It's important it has AVR, and important it has filtering.
3) I plug digital things into this AVR UPS, but I plug analog things (like my A/V receiver) into an 80 dB noise filtering extra surge suppressor and filter, that's also a power strip (this is a Tripp Lite).
4) I also have a Transcendent Sound Balanced Power supply (about $500 for 1000 VA) that I can move around to reduce noise. However, the current set-up is so well behaved that I haven't actually had to plug it in. If it stays that way, I might just list it for sale :-)

You will note that the power amplification is not protected by an UPS or filtering. That's unfortunate, but the theory is that anything really bad is more likely to happen when the system is off (and the relay insulates) so I'm taking my chances. The AC circuitry in my speakers is also first rate, so I don't worry too much about that.

Additionally, I run most gear through the AVR/filtered part of the UPS, and only run the stuff that really needs power-down protection through the battery half (this means a TiVo, a network router, and a Mac Mini). In that sense, that box serves two purposes at once!

Now, I believe I paid $149 for the AVR UPS, and another $45 for the Tripp Lite, and I believe that gives me enough of a benefit without paying too much. So far, it seems to work, although I haven't broken in or really tuned the system carefully yet.

... is there any benefit to 20 amps over 15 for whatever gear might be connected to it?


My neighbor, the electrical supply salesman, is suggesting a whole-house surge protector called a "Cutler Hammer," about $43. I'm still left with plugging in a bunch of gear, including the digital gear and my pre/pro (presumably not my two amps or my powered sub), . As mentioned earlier, I'm leaning toward a used Furman (I like the rack lights) for the job. Is there any benefit to going with a 20 amp instead of a 15 amp device?

Yes, but not huge. If you have 15 amp circuits for you'r recepticles then you could use either with the 20 amp having the advatage of being more robust in design. If you have 20 amp circuits for you recepticles you would be best served if you get the 20 amp unit, but this all REALLY depends on how many amps the load draws that is connected to the unit.

Cutler Hammer is a brand and not a product. You could find similar surges built by any electrical manufacturer, but C-H is a good manufacturer and the 43 is a good value.

Thanks! Yes, I plan to upgrade to 20 amp circuits.

Well to upgrade the circuits you need to change the breaker to a 20a breaker, check and or change the wire to 20a rated wire (#12 in most cases, but this depends on a lot of things including local codes), and of course the wall outlet(receptacle) to 20amps. All that being done you will only be good for up to 16amps due to the heating elements and reduced cooling inside the breaker panel, but this is much better than the 12amps to 15Amp circuit provided for the same reasons. You only get 80% of the breaker rating for residential services.

How important are the 10 awg lines from the breaker box to the recepticles, if my run is only ~15'?

10 awg is overkill -- you should get away just fine with 12 awg, assuming it's a 20 A or less line (and assuming that's to code in your locale).

Cutler Hammer is a brand and not a product. You could find similar surges built by any electrical manufacturer, but C-H is a good manufacturer and the 43 is a good value.

Correct. But I don't know of any C-H whole house surge arrester that costs less that 120 USD. :confused:

OK. I know here in Mexico we're paying much more for electrical and electronic devices than you're paying there in the USA. :(

Maybe it's one of those units that replaces two breakers? Weren't they bought out by Eaton or someone?

Weren't they bought out by Eaton or someone?

Yes, Eaton includes Culter-Hammer & Westinghouse just like Schneider Electric is now the parent company of Square D & Federal (FPE).

Additionally, I run most gear through the AVR/filtered part of the UPS, and only run the stuff that really needs power-down protection through the battery half (this means a TiVo, a network router, and a Mac Mini). In that sense, that box serves two purposes at once!



Are you sure that you are getting AVR through the non-battery backup plugs on your UPS? I would guess that you have surge protection only, and AVR only applies to the plugs which also provide battery backup.

I could be wrong, but this is based on my experience with a Tripp Lite Smart750XL, other UPS' may vary.

Thanks! Yes, I plan to upgrade to 20 amp circuits. No need to do this unless your breakers trip under everyday use. Even then, consider dedicated home runs for heavy loads. 15amp breakers are safer for you and yours than 20amp.

No need to do this unless your breakers trip under everyday use. Even then, consider dedicated 15amp home runs for difficult loads. 15amp breakers are safer for you and yours than 20amp.

Hmmm. It's always something! Seems the conventional wisdom is to upgrade to dedicated 20 amp circuits, but other than that, I know nothing about such things. What is the safety issue?

Hmmm. It's always something! Seems the conventional wisdom is to upgrade to dedicated 20 amp circuits, but other than that, I know nothing about such things. What is the safety issue? A breaker is a safety device first and foremost designed to interrupt power in the case of a short circuit. The sooner it does that the better for the poor soul who maybe the conduit to ground for that fault current.

Yes, Eaton includes Culter-Hammer & Westinghouse just like Schneider Electric is now the parent company of Square D & Federal (FPE).

Thanks. I confirmed that Eaton owns Cutler-Hammer. Schneider Group includes Square D, Federal Pacific and Telemecanique.

BTW, I think the Eaton's guide to surge suppression is quite informative:

http:/http://www.eaton.com/ecm/groups/public/@pub/@eaton/@ee/documents/content/sa01005003e.pdf

It's even more informative when you fix the extra http's! LOL. To me, it's worth printing out and reading it a few times. I love computers, but hate multipage documents.

It's even more informative when you fix the extra http's! LOL.

Ah! Did you notice my extra http's? LOL. :D

A breaker is a safety device first and foremost designed to interrupt power in the case of a short circuit. The sooner it does that the better for the poor soul who maybe the conduit to ground for that fault current.


This would make sense if fault currents were very low, however most are greater than 4 times the breaker rating which puts the trip times close to thier minimum (around .1 seconds) so 15A or 20 amps you are going to be about the same safety wise.

I will agree if you do not need the extra capacity provided by the 20 amp circuit then why spend the extra money.

I had the power line to my house short out at the hydro pole and that fried a computer, microwave, my alarm system and numerous other things. (BC Hydro paid to replace everything.) None of my audio equipment was touched and it was just plugged into a cheap Monster unit that I picked up used. Whole house protection would likely have saved me a whole lot of hassle.

This would make sense if fault currents were very low, however most are greater than 4 times the breaker rating which puts the trip times close to thier minimum (around .1 seconds) so 15A or 20 amps you are going to be about the same safety wise.
NEC defines a current -limiting protective device as one that cuts off a fault current in less than one-half cycle or .008333 seconds for a 60hz supply which prevents the short circuit from building up to their full available values.
The bimetallic element in the typical thermal-magnetic 15amp breaker begins to move .1 to .2 milli seconds (the typical voltage rise time of a coil) earlier to unlatch the inner tripping mechanism than a 20amp breaker. That time difference is not minor because 10% to 90% of the wave crest is delivered within it.
So the max short circuit current available is more a function of the ampere rating of the branch breaker and not a function of the max short circuit current available on the secondary of your pole transformer or the ampere rating of the main breaker as you seem to indicate.

I will agree if you do not need the extra capacity provided by the 20 amp circuit then why spend the extra money.You only need the extra capacity if your loads frequently trip your current breaker during normal use.

NEC defines a current -limiting protective device as one that cuts off a fault current in less than one-half cycle or .008333 seconds for a 60hz supply which prevents the short circuit from building up to their full available values.
The bimetallic element in the typical thermal-magnetic 15amp breaker begins to move .1 to .2 milli seconds (the typical voltage rise time of a coil) earlier to unlatch the inner tripping mechanism than a 20amp breaker. That time difference is not minor because 10% to 90% of the wave crest is delivered within it.
So the max short circuit current available is more a function of the ampere rating of the branch breaker and not a function of the max short circuit current available on the secondary of your pole transformer or the ampere rating of the main breaker as you seem to indicate.
You only need the extra capacity if your loads frequently trip your current breaker during normal use.


Well from a protection stand point it is important to know when protection is initiated, however time to CLEAR the fault is just as important. The NEC standard for branch circuits to clear faults is .1 seconds. so yes the 15 amp will clear in .101 versus the 20 amp breaker that clears on .102 seconds It still delivers 6 cycles (estimated) of fault current. I am just pointing out in terms of 'safety' these two systems are about equal and the 20 circuit should not be somehow represented as less safe.

I don't remember saying anything about available fault current of a pole mounted transformer, but that is going to be allot higher than what the branch could deliver anyway.

NEC defines a current -limiting protective device as one that cuts off a fault current in less than one-half cycle or .008333 seconds for a 60hz supply which prevents the short circuit from building up to their full available values.


This is not the NEC Definition and Current limiting device is different than a molded case residential circuit breaker.

Art 240 Definitions

Current limiting Overcurrent Protective Device- A device that, when interupting currents in its current-limiting range, REDUCES the current flowing in the faulted circuit to a magnitude substatially less than that obtainable in the same circuit in the device were replaced with a solid conductor having comparable impedance.

These are typically Fuses or inductors install within breakers.

Anyway I have a correcttion that the fault clearing time is a NEMA rating rather than an NEC rating.

This is not the NEC Definition and Current limiting device is different than a molded case residential circuit breaker.

Art 240 Definitions

Current limiting Overcurrent Protective Device- A device that, when interupting currents in its current-limiting range, REDUCES the current flowing in the faulted circuit to a magnitude substatially less than that obtainable in the same circuit in the device were replaced with a solid conductor having comparable impedance.
Yes, this is the wording, but the implication is that the solenoid must interrupt before the completion of one-half cycle or max available SHORT CIRCUIT current is delivered.
Well from a protection stand point it is important to know when protection is initiated, however time to CLEAR the fault is just as important. The NEC standard for branch circuits to clear faults is .1 seconds. so yes the 15 amp will clear in .101 versus the 20 amp breaker that clears on .102 seconds It still delivers 6 cycles (estimated) of fault current. I am just pointing out in terms of 'safety' these two systems are about equal and the 20 circuit should not be somehow represented as less safe.Its unfortunate that you choose to label OVERLOAD current as SHORT CIRCUIT/FAULT current.
The bimetallic element of a 15amp breaker will typically trip several cycles ahead of that of a 20amp breaker for an equivalent overload. I was being overly conservative previously.
The solenoid of a 15 amp breaker, though with a similar response time of that of a 20amp breaker, will still limit significantly more fault current

Yes, this is the wording, but the implication is that the solenoid must interrupt before the completion of one-half cycle or max available SHORT CIRCUIT current is delivered.


Yes but you miss the bigger point of the fact that breakers have to mechnaically move to inturpt fault current and that take time. In this case they are about equal.

Its unfortunate that you choose to label OVERLOAD current as SHORT CIRCUIT/FAULT current.
The bimetallic element of a 15amp breaker will typically trip several cycles ahead of that of a 20amp breaker for an equivalent overload. I was being overly conservative previously.
The solenoid of a 15 amp breaker, though with a similar response time of that of a 20amp breaker, will still limit significantly more fault current

I am clearly NOT talking about overload current.
I have attached a typical TCC if you want to review and if you want you can do the the calc, but they will both clear a fault between .15 and .18 seconds during a short circuit. The quick calc I did showed the 20 amp clearing faster at .16 second and the 15 amp clearing in .17 seconds. The 20 amp fault released more energy but both were very close in terms of damage and burns.

Sorry loaded the GF TCC here is the correct

The legend itslelf says long-time delay and instantaneous, part of the curve is overload current.

Yes and for FAULT (short circuit) current to typically use the inst curves. Overload was a different issue and really is in the same boat as far as safety since the larger breaker uses larger wire and is capable of carrying more before reaching its thermal limit

Yes and for FAULT (short circuit) current to typically use the inst curves. Overload was a different issue and really is in the same boat as far as safety since the larger breaker uses larger wire and is capable of carrying more before reaching its thermal limit
All due respect my friend, that curve is mostly, if not entirely, slow blow time-current characteristics for the bimetallic element of that particular circuit breaker. tcc's for short circuit current are literally instantaneous. There is no travel time of the latch to consider there is only arcing to consider with respect to let-through. If you find it difficult to believe that an electro-mechanical transducer, such is the solenoid and the tripping mechanism, can move that fast then consider a tweeter motor and diaphragm and the typical 10khz+ frequencies they attain. 60hz cycle is child’s play by comparison.

All due respect my friend, that curve is mostly, if not entirely, slow blow time-current characteristics for the bimetallic element of that particular circuit breaker. tcc's for short circuit current are literally instantaneous. There is no travel time of the latch to consider there is only arcing to consider with respect to let-through. If you find it difficult to believe that an electro-mechanical transducer, such is the solenoid and the tripping mechanism, can move that fast then consider a tweeter motor and diaphragm and the typical 10khz+ frequencies they attain. 60hz cycle is child’s play by comparison.


For currents above 15 times the breaker's rating( 300 amps), that unit goes into the magnetic clearing regime of operation. Between 800 and 6,400 amps fault current, the device is guaranteed to clear in at least 16 milliseconds.

Below 300 amps, the device operates thermally.

Cheers, John

For currents above 15 times the breaker's rating( 300 amps), that unit goes into the magnetic clearing regime of operation.
Thank you John, now that you've said it, I presume its now taken as fact.

Thank you John, now that you've said it, I presume its now taken as fact.

That Neutron guy IS pretty smart -- especially after a brain blast.

Thank you John, now that you've said it, I presume its now taken as fact.

Now now, be nice. You are more than welcome to provide a link to show how I am wrong..

All one has to do is review the breaker stuff. If you google "how it works" for breaker operation, they show how the magnetic aspect of the device works.

While the magnetic part may pull the trip mechanism very quicky at extreme currents, the spring still requires a finite time to pull the mass of the internals away from the contacts. So it is not the magnetic field force which opens the device, but instead, the magnetic force releases the spring mechanism which in turn opens the breaker. (the video shows how it works.)

Here's the link:
http://electronics.howstuffworks.com/circuit-breaker2.htm


Help-r: What arc flash software are you using to calculate fault energy? Does your software actually calculate flash energy in excess of 8 Cal/cm^2 for residential voltage levels??

We don't consider anything below 240 volts as being arc flash "worthy", nor anything below 225 amps. Those are the boundaries between NFPA 70E category O and category 2. Since I teach this as part of my advanced electrical safety course, new information would be much appreciated.

Thanks,

Cheers, John

Thank you John, now that you've said it, I presume its now taken as fact.

It is fact.

Larger breakers have 4 discrete operating regions - L, S, I, and G. These equate to Long, Short, Instantaneous, and Ground.

Smaller molded-case breakers (like those in a residential load center) generally are pure thermal-mag; Thermal long-time, and Magnetic instantaneous. GFCI breakers add the 'G' function by sensing ground current (indirectly); Arc-fault breakers add a totally separate protective function that is generally not duplicated in a power breaker trip unit. Keep in mind, though, that a circuit breaker's basic function is to protect the WIRING from faults, not the LOAD.

Now, I will disagree with the statement that you don't need/want a 20A circuit unless you are heating up a 15A circuit. The one good reason to have a 20A circuit is transient current demand. Using a 20A circuit (with 12ga wire) will give you a smaller voltage drop under transient demand situations. It also lowers the source impedance, which makes the voltage more stable, and less likely to respond to noise.

FWIW, I have had very good results with the Cutler-Hammer TVSS whole-house units. They are a very well-designed product that has gone through several generations of refinement. Granted, it's not a complete subsititure for point-of-use TVSS, but if you have any signficant amount of electronic equipment, you should consider a whole-house unit like the one mentioned above.

Help-r: What arc flash software are you using to calculate fault energy? Does your software actually calculate flash energy in excess of 8 Cal/cm^2 for residential voltage levels??

We don't consider anything below 240 volts as being arc flash "worthy", nor anything below 225 amps. Those are the boundaries between NFPA 70E category O and category 2. Since I teach this as part of my advanced electrical safety course, new information would be much appreciated.

How could you get that much energy (8 cal) downstream of the panelboard? It would seem to me that even a bolted fault couldn't get there with a single-phase 120VAC line from a resi board.......???? I've always assumed that a resi panel was level 0 or 1 at most....

Now now, be nice. You are more than welcome to provide a link to show how I am wrong..

All one has to do is review the breaker stuff. If you google "how it works" for breaker operation, they show how the magnetic aspect of the device works.

While the magnetic part may pull the trip mechanism very quicky at extreme currents, the spring still requires a finite time to pull the mass of the internals away from the contacts. So it is not the magnetic field force which opens the device, but instead, the magnetic force releases the spring mechanism which in turn opens the breaker. (the video shows how it works.)

Here's the link:
http://electronics.howstuffworks.com/circuit-breaker2.htm


Cheers, John
The spring is part of the trip-free operating mechanism of that breaker of which the internal tripping mechanism works independently of to initially open the circuit. the moment of inertia of the spring/mass is irrelevant to tcc.


Now, I will disagree with the statement that you don't need/want a 20A circuit unless you are heating up a 15A circuit. The one good reason to have a 20A circuit is transient current demand. Using a 20A circuit (with 12ga wire) will give you a smaller voltage drop under transient demand situations. It also lowers the source impedance, which makes the voltage more stable, and less likely to respond to noise.

. Unless those transients approach the fault current levels of a 15amp breaker then there is no advantage to the safer 15amp dedicated run.

Unless those transients approach the fault current levels of a 15amp breaker then there is no advantage to the safer 15amp dedicated run.

Sure about that?

Try measuring the actual AC impedance of a 15A breaker and 14ga wire vs a 20A breaker and 12 ga wire at, say, 1 kHz, with a demanded instantaneous current of 100A.

Keep in mind that the initial inrush current of a normal dry-type transformer can be as much as 12x the rated load current. Now, how much instantaneous current do you think is drawn by a linear power supply in a large power amp that has just exhausted its filter caps? A 1000W RMS subwoofer amp would have to be designed for a steady-state draw of about 10A (counting impedance losses and thermal inefficiencies). Now, the 12x inrush current = ???? How much more is added by the charging current for the caps and the actual load itself?

Steady-state draw and instantaneous current are NOT the same thing, and the fact that a 35A draw will eventually open a 20A breaker does NOT mean that the breaker/circuit isn't regularly called upon to supply far more than that for a few cycles at a time.

You also stated that you believe the 15A run to be safer. Safer in what way? Neither circuit has enough available fault energy to be a serious threat from an arc flash standpoint, and both have enough current available to kill you, if (im)properly applied.......

For currents above 15 times the breaker's rating( 300 amps), that unit goes into the magnetic clearing regime of operation. Between 800 and 6,400 amps fault current, the device is guaranteed to clear in at least 16 milliseconds.

Below 300 amps, the device operates thermally.

Cheers, John


You assume that the POS circuit breaker follows the tolerance curves indicated by the manufacturer. When we test these breakers (very rarely) we find anywhere from 5-25% failure rate.


We can all agree that 'Instantaneous' means- without any intentional delay....right. And yes, the breaker, if operating properly should clear in less than two cycles.

Sure about that?

Try measuring the actual AC impedance of a 15A breaker and 14ga wire vs a 20A breaker and 12 ga wire at, say, 1 kHz, with a demanded instantaneous current of 100A.



AC impedance of the 15A/20A breaker will be pretty close, I can't believe that the 14WG vs 12AWG is all that different either.

How could you get that much energy (8 cal) downstream of the panelboard? It would seem to me that even a bolted fault couldn't get there with a single-phase 120VAC line from a resi board.......???? I've always assumed that a resi panel was level 0 or 1 at most....


If the circuit breakers don't work....you have yourself an arc flash party. Why does everyone assume that the protective devices work....especially right out of the factory???

I have been performing arc flash analysis using ETAP for the past few years. I always preface my presentations with the requirement that the customer must perform maintenance on the protective devices to ensure compliance with manufacturer tolerances. The problems I see in the field consist of:

1) Older protective equipment which has not been recently tested, excercised and maintained. This protective equipment may not operate when called upon or trips well outside of tolerances.
2) Improperly applied protective settings or lack of coordination. Many design/build jobs have coordination problems when the protective equipment setpoints are left at the factory settings.
3) Utility service changes or upgrades. If the utility changes the transformer feeding your facility or the residential load (increases the size) the available short circuit current generally increases too.

This is getting off track though......

If the circuit breakers don't work....you have yourself an arc flash party. Why does everyone assume that the protective devices work....especially right out of the factory???

Well, you have to start with some sort of assumption, right? Otherwise, every journeyman electrician would be walking around in a 40-cal suit - hardly a reasonable approach.

I always preface my presentations with the requirement that the customer must perform maintenance on the protective devices to ensure compliance with manufacturer tolerances.

True - and followed far too rarely.

1) Older protective equipment which has not been recently tested, excercised and maintained. This protective equipment may not operate when called upon or trips well outside of tolerances.

Also true.

2) Improperly applied protective settings or lack of coordination. Many design/build jobs have coordination problems when the protective equipment setpoints are left at the factory settings.

I have to disagree with you there. Most factories (I can't speak for all, but I have first-hand knowledge of some of the major manufacturers) pre-set all of their trip units and/or protective relays at minimum settings. Yes, this can cause coordination problems, but it is generally in the direction of being too conservative, and opening too soon, or too far up the distribution scheme (removing power from too much of the system).

3) Utility service changes or upgrades. If the utility changes the transformer feeding your facility or the residential load (increases the size) the available short circuit current generally increases too.

Yes, and far too often, the coordination study is not fully updated, much less any arc-flash information (if there was any to begin with).

This is getting off track though......

Yup. :o It's a good topic of discussion, though..... :D

You also stated that you believe the 15A run to be safer. Safer in what way? Neither circuit has enough available fault energy to be a serious threat from an arc flash standpoint, and both have enough current available to kill you, if (im)properly applied.......

Thank you, as this was the original disagreement.

The spring is part of the trip-free operating mechanism of that breaker of which the internal tripping mechanism works independently of to initially open the circuit. the moment of inertia of the spring/mass is irrelevant to tcc.


Wrong this had everything to do with TCC. Without knowing fault clearing time(the upper side of the shaded area) then how would you know when the fault was interupted? and better yet how would you know that the next breaker or fuse didn't open also or before?

Help-r: What arc flash software are you using to calculate fault energy? Does your software actually calculate flash energy in excess of 8 Cal/cm^2 for residential voltage levels??

I just did a quick calc by hand, we mostly work in the med/high voltage range so I don't have alot of residential stuff lyinjg around. S and C, synergee, excel on some stff, and matlab. My point was that I disagreed that the 20 circuit was somehow less safe then a 15 amp circuit. I just didn't want the OP to choose what circuit he was going to use based on that assumption.

You assume that the POS circuit breaker follows the tolerance curves indicated by the manufacturer. When we test these breakers (very rarely) we find anywhere from 5-25% failure rate.


We can all agree that 'Instantaneous' means- without any intentional delay....right. And yes, the breaker, if operating properly should clear in less than two cycles.


Yes, I agree that the breaker or relay will react "instantly" but like you said it takes time for the contacts to move and this rarely happens with these level of breakers. A rule of thumb using these has always been .1 seconds for real world applications.

Sure about that?

Try measuring the actual AC impedance of a 15A breaker and 14ga wire vs a 20A breaker and 12 ga wire at, say, 1 kHz, with a demanded instantaneous current of 100A.

Keep in mind that the initial inrush current of a normal dry-type transformer can be as much as 12x the rated load current. Now, how much instantaneous current do you think is drawn by a linear power supply in a large power amp that has just exhausted its filter caps? A 1000W RMS subwoofer amp would have to be designed for a steady-state draw of about 10A (counting impedance losses and thermal inefficiencies). Now, the 12x inrush current = ???? How much more is added by the charging current for the caps and the actual load itself?
I don't know how much instantaneous current is demanded, your point being its significant. However, given the use of soft start circuitry and non-linear, ultra efficient, switching power supplies in most subwoofers, how common an occurrence is your example nowadays. AC impedance of the 15A/20A breaker will be pretty close, I can't believe that the 14WG vs 12AWG is all that different either. It isn't. This belief that a 20amp circuit is better than a 15amp circuit is an audiophile myth that makes dangerous assumptions about brekaer performance.

I don't know how much instantaneous current is demanded, your point being its significant. However, given the use of soft start circuitry and non-linear, ultra efficient, switching power supplies in most subwoofers, how common an occurrence is your example nowadays.

The basic premise still holds. If you are operating a device which has nominal power draw that is near the limits of the circuit (> 50%), then you must assume that its peak current demand is significantly higher. Granted, a SMPS will have a far smaller inrush than a linear design, but it will still draw a lot more current both on startup and if/when the filter caps are depleted by peak signals. This is when the lower source impedance provided by the larger 12ga wire matters.

Wrong this had everything to do with TCC. Without knowing fault clearing time(the upper side of the shaded area) then how would you know when the fault was interupted? and better yet how would you know that the next breaker or fuse didn't open also or before?
You missed the point completely, I'm contending that the solenoid and trip bar move first to open the circuit; A typical residential thermal mag breaker has a spring loaded 'trip-free' mechanism so that even if the handle is held in the on position the primary 'internal trip mechanism' (solenoid and trip bar) will still open the circuit. The 'internal tripping mechanism' is the primary mechanism by which the circuit initially opens, independent of the spring loaded 'trip-free' mechanism. So the moment of inertia of the spring/mass of the 'trip free' mechanism has no relevancy to the TCC.

How could you get that much energy (8 cal) downstream of the panelboard? It would seem to me that even a bolted fault couldn't get there with a single-phase 120VAC line from a resi board.......???? I've always assumed that a resi panel was level 0 or 1 at most....

Hey, that was my question... :p

We don't even consider 1. Everything at work is either 0, 2, or 4. Resi we consider by default, 0.

Can't tell if bolted fault is worse than say an arc current half that. The people here responsible for the calcs seem to class and label 220 panels 0.

Cheers, John

The spring is part of the trip-free operating mechanism of that breaker of which the internal tripping mechanism works independently of to initially open the circuit. the moment of inertia of the spring/mass is irrelevant to tcc.


As you can see in the simple video, the unit makes no distinction between a thousand amps and ten thousand. The spring based movement is independent of the force created by the current. For the specification presented by help-r, the right side (magnetic trip) of the graph flatlines at 16 milliseconds. If the mass of the mechanism came into play, that would not be a flat line at 16 milliseconds all the way out to 6400 amps. The transition curvature between thermal and magnetic is the region where the mass of the system comes into play.

Do you have any links or information for residential breakers which indicate they are instantaneous out to 10 kiloamps, or are you workin here without a net? :p

Cheers, John

You assume that the POS circuit breaker follows the tolerance curves indicated by the manufacturer. When we test these breakers (very rarely) we find anywhere from 5-25% failure rate.


Actually, I assumed nothing, but was merely explaining the different trip regimes which appeared on the graph that was presented by help-r. Are you talking failures out of the box, or in situ?

Failures? sheesh, why aren't you using square-D??? We had a guy in a coupla months ago to give us a two day NEC class....he was chair of one of the groups for chapter 4, I believe...what a phenomenal guy, I think he knows every single thing there is in the current code, up to and including the page number of every graph, diagram, everything...he liked square-D.


Cheers, John

AC impedance of the 15A/20A breaker will be pretty close, I can't believe that the 14WG vs 12AWG is all that different either.


12 to 14 is a milliohm per foot difference, 1.7 to 2.7. For a 50 foot run, that's 100 milliohms diff. A 100 amp transient will be 10 volts difference in sag, 17 volts to 27.

Inductance....If you assume identical insu thickness, #14 will be slightly more. But I don't think that is as big as the resistance change.

Cheers, John

1) Older protective equipment which has not been recently tested, excercised and maintained. This protective equipment may not operate when called upon or trips well outside of tolerances.

Oh man, you got that right..

3) Utility service changes or upgrades. If the utility changes the transformer feeding your facility or the residential load (increases the size) the available short circuit current generally increases too.

That is the entire basis for the arc flash problem we now have. Legacy equipment didn't have the problem, but as the utility changes the upstream xfmrs to higher efficiency, the fault currents have increased far beyond the equipment's physical capability to contain the explosion.

Utilities are responsible for limiting fault current to residential customers, but are not under such constraints for industrial ones. Given my square D panel has 10Kamp fault ratings, I make the "assumption" that the utility has to limit the bolted fault capability to that level. Again so it is clear, that is my assumption only.



Cheers, John

Actually John, my head stop hurting long enough for me to gather that we agreed all along.

Actually John, my head stop hurting long enough for me to gather that we agreed all along.

Ya know, I was beginning to think that myself. ;)

Cheers, John

Well, you have to start with some sort of assumption, right? Otherwise, every journeyman electrician would be walking around in a 40-cal suit - hardly a reasonable approach.

What, you don't like dressin up like Marty in Back to the future??? "I COME FROM THE PLANET VULCAN"!!

Cheers, John

Actually, I assumed nothing, but was merely explaining the different trip regimes which appeared on the graph that was presented by help-r. Are you talking failures out of the box, or in situ?

Failures? sheesh, why aren't you using square-D??? We had a guy in a coupla months ago to give us a two day NEC class....he was chair of one of the groups for chapter 4, I believe...what a phenomenal guy, I think he knows every single thing there is in the current code, up to and including the page number of every graph, diagram, everything...he liked square-D.


Cheers, John


Pick your poison, we have encountered similar quality problems with most equipment (GE, Siemens, Square D, Cutler Hammer). Yes, we are talking failures right out of the factory sealed box. Not all failures are trip tolerance issues, some consist of poor contact resistance, poor insulation values and even operating issues. I have returned brand new breakers because they will not close.

Generally, Square D has nice products, but you have to realize that they only do batch testing of this stuff. Maybe one out of one-hundred breakers are tested at the factory. :confused:

Well, you have to start with some sort of assumption, right? Otherwise, every journeyman electrician would be walking around in a 40-cal suit - hardly a reasonable approach.

You are correct, but I was trying to get the point across that most new installations never have testing performed. Besides ensuring proper operation of the system, the owner gets a baseline performance report.

I have to disagree with you there. Most factories (I can't speak for all, but I have first-hand knowledge of some of the major manufacturers) pre-set all of their trip units and/or protective relays at minimum settings. Yes, this can cause coordination problems, but it is generally in the direction of being too conservative, and opening too soon, or too far up the distribution scheme (removing power from too much of the system).

In my experience with circuit breaker switchboards, most of the time, the breakers are set to min settings. However, every bolted pressure switch with ground fault I test seems to come from the factory at max. This is not the case for all equipment but.......




Yup. :o It's a good topic of discussion, though..... :D

We generally have good discussions of such topics at the annual NETA conference. All of us test geeks get together there.

Yes, I agree that the breaker or relay will react "instantly" but like you said it takes time for the contacts to move and this rarely happens with these level of breakers. A rule of thumb using these has always been .1 seconds for real world applications.


I have a test set which I use to inject current into circuit breakers for testing, unfortunately, the test set is not accurate below about 0.2 seconds (used for short time overcurrent testing). Even the POS residential breakers typically test well in this regard.

It isn't. This belief that a 20amp circuit is better than a 15amp circuit is an audiophile myth that makes dangerous assumptions about brekaer performance.


I don't make any assumptions about breaker performance....see posts for clarification.

I don't make any assumptions about breaker performance....see posts for clarification.
I never implied that you did.

You missed the point completely, I'm contending that the solenoid and trip bar move first to open the circuit; A typical residential thermal mag breaker has a spring loaded 'trip-free' mechanism so that even if the handle is held in the on position the primary 'internal trip mechanism' (solenoid and trip bar) will still open the circuit. The 'internal tripping mechanism' is the primary mechanism by which the circuit initially opens, independent of the spring loaded 'trip-free' mechanism. So the moment of inertia of the spring/mass of the 'trip free' mechanism has no relevancy to the TCC.


I am not talking about the handle on the breaker. I agree that the solenoid acts very quickly, but the current carrying contacts (stationary and moving contacts) that actually break the current and stop the fault is where you stop timing from a protection stand point. And in the inst region on the graph it still takes a certain amount of time for the breaker to be able to stop the fault current from flowing, such as getting enough distance to extingush the arc drawn by the moving contacts. I never meant to disagree with you about the the action of the solenoid but you need to consider the other side of the equation. The breaker must sense a fault then stop it. The solenoid does the sensing part but the contacts opening stops it. And on the graph and in practice the 15amp breaker and 20 amp breaker perform them same in the inst region. and these breakers aren't very accurate we have bench tested a couple and you vary from 4 cycles to 12 cycles.

Pick your poison, we have encountered similar quality problems with most equipment (GE, Siemens, Square D, Cutler Hammer). Yes, we are talking failures right out of the factory sealed box. Not all failures are trip tolerance issues, some consist of poor contact resistance, poor insulation values and even operating issues. I have returned brand new breakers because they will not close.

Generally, Square D has nice products, but you have to realize that they only do batch testing of this stuff. Maybe one out of one-hundred breakers are tested at the factory. :confused:

Yeah we see this all the time too. We currently got a dozen K line breaker that fail to test because the trip coil fail to reset on a breaker opening. you would think there would be better quality control from the factories considering the liability involved.

Yeah we see this all the time too. We currently got a dozen K line breaker that fail to test because the trip coil fail to reset on a breaker opening. you would think there would be better quality control from the factories considering the liability involved.

You'd be amazed at how many times the faults you see are actually caused by shipping 'incidents'. I have seen instances where there was a solid, verifiable factory witness test report (i.e., the customer watched it function prior to shipping) and there still were faults that showed up after delivery and installation.

Bottom line: Proper startup and commissioning is NOT an optional step for any equipment of significant size feeding loads you care about. And yes, you have to do the maintenance.

Bottom line: Proper startup and commissioning is NOT an optional step for any equipment of significant size feeding loads you care about. And yes, you have to do the maintenance.

Yep, NFPA 70B, NEC and NETA all agree on these points.

One of my favorite mumblings is ' We don't have enough time/money to do the job right the first time, but we surely have the time and money to do it right the second time...or third ....' :p

Or another great one, in the name of maintenance.... "Pay me now, or pay me a lot more later'.

"Pay me now, or pay me a lot more later'

^^^^^^ One of my favorites

or

"What do the manufacturers know anyway"